@@ -13,10 +13,12 @@
  * LICENSE.GPLv2 or LICENSE.GPLv3 respectively included in the packaging of this
  * file.
  */
 
 #import "OFString.h"
+
+OF_ASSUME_NONNULL_BEGIN
 
 #if !defined(OF_CONSTANT_STRING_M) && \
     defined(OF_APPLE_RUNTIME) && !defined(__OBJC2__)
 # ifdef __cplusplus
 extern "C" {
@@ -36,5 +38,7 @@
 {
 	char *_cString;
 	unsigned int _cStringLength;
 }
 @end
+
+OF_ASSUME_NONNULL_END